GPS Applications in Space
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Analysis of Perturbations and Station-Keeping Requirements in Highly-Inclined Geosynchronous Orbits
ANALYSIS OF PERTURBATIONS AND STATION-KEEPING REQUIREMENTS IN HIGHLY-INCLINED GEOSYNCHRONOUS ORBITS Elena Fantino(1), Roberto Flores(2), Alessio Di Salvo(3), and Marilena Di Carlo(4) (1)Space Studies Institute of Catalonia (IEEC), Polytechnic University of Catalonia (UPC), E.T.S.E.I.A.T., Colom 11, 08222 Terrassa (Spain), [email protected] (2)International Center for Numerical Methods in Engineering (CIMNE), Polytechnic University of Catalonia (UPC), Building C1, Campus Norte, UPC, Gran Capitan,´ s/n, 08034 Barcelona (Spain) (3)NEXT Ingegneria dei Sistemi S.p.A., Space Innovation System Unit, Via A. Noale 345/b, 00155 Roma (Italy), [email protected] (4)Department of Mechanical and Aerospace Engineering, University of Strathclyde, 75 Montrose Street, Glasgow G1 1XJ (United Kingdom), [email protected] Abstract: There is a demand for communications services at high latitudes that is not well served by conventional geostationary satellites. Alternatives using low-altitude orbits require too large constellations. Other options are the Molniya and Tundra families (critically-inclined, eccentric orbits with the apogee at high latitudes). In this work we have considered derivatives of the Tundra type with different inclinations and eccentricities. By means of a high-precision model of the terrestrial gravity field and the most relevant environmental perturbations, we have studied the evolution of these orbits during a period of two years. The effects of the different perturbations on the constellation ground track (which is more important for coverage than the orbital elements themselves) have been identified. We show that, in order to maintain the ground track unchanged, the most important parameters are the orbital period and the argument of the perigee. -
Astrodynamics
Politecnico di Torino SEEDS SpacE Exploration and Development Systems Astrodynamics II Edition 2006 - 07 - Ver. 2.0.1 Author: Guido Colasurdo Dipartimento di Energetica Teacher: Giulio Avanzini Dipartimento di Ingegneria Aeronautica e Spaziale e-mail: [email protected] Contents 1 Two–Body Orbital Mechanics 1 1.1 BirthofAstrodynamics: Kepler’sLaws. ......... 1 1.2 Newton’sLawsofMotion ............................ ... 2 1.3 Newton’s Law of Universal Gravitation . ......... 3 1.4 The n–BodyProblem ................................. 4 1.5 Equation of Motion in the Two-Body Problem . ....... 5 1.6 PotentialEnergy ................................. ... 6 1.7 ConstantsoftheMotion . .. .. .. .. .. .. .. .. .... 7 1.8 TrajectoryEquation .............................. .... 8 1.9 ConicSections ................................... 8 1.10 Relating Energy and Semi-major Axis . ........ 9 2 Two-Dimensional Analysis of Motion 11 2.1 ReferenceFrames................................. 11 2.2 Velocity and acceleration components . ......... 12 2.3 First-Order Scalar Equations of Motion . ......... 12 2.4 PerifocalReferenceFrame . ...... 13 2.5 FlightPathAngle ................................. 14 2.6 EllipticalOrbits................................ ..... 15 2.6.1 Geometry of an Elliptical Orbit . ..... 15 2.6.2 Period of an Elliptical Orbit . ..... 16 2.7 Time–of–Flight on the Elliptical Orbit . .......... 16 2.8 Extensiontohyperbolaandparabola. ........ 18 2.9 Circular and Escape Velocity, Hyperbolic Excess Speed . .............. 18 2.10 CosmicVelocities -
GPS and GLONASS Vector Tracking for Navigation in Challenging Signal Environments
GPS and GLONASS Vector Tracking for Navigation in Challenging Signal Environments Tanner Watts, Scott Martin, and David Bevly GPS and Vehicle Dynamics Lab – Auburn University October 29, 2019 2 GPS Applications (GAVLAB) Truck Platooning Good GPS Signal Environment Autonomous Vehicles Precise Timing UAVs 3 Challenging Signal Environments • Navigation demand increasing in the following areas: • Cites/Urban Areas • Forests/Dense Canopies • Blockages (signal attenuation) • Reflections (multipath) 4 Contested Signal Environments • Signal environment may experience interference • Jamming . Transmits “noise” signals to receiver . Effectively blocks out GPS • Spoofing . Transmits fake GPS signals to receiver . Tricks or may control the receiver 5 Contested Signal Environments • These interference devices are becoming more accessible GPS Jammers GPS Simulators 6 Traditional GPS Receiver Signals processed individually: • Known as Scalar Tracking • Delay Lock Loop (DLL) for Code • Phase Lock Loop (PLL) for Carrier 7 Traditional GPS Receiver • Feedback loops fail in the presence of significant noise • Especially at high dynamics Attenuated or Distorted Satellite Signal 8 Vector Tracking Receiver • Process signals together through the navigation solution • Channels track each other’s signals together • 2-6 dB improvement • Requires scalar tracking initially 9 Vector Tracking Receiver Vector Delay Lock Loop (VDLL) • Code tracking coupled to position navigation • DLL discriminators inputted into estimator • Code frequencies commanded by predicted pseudoranges -
Comparing Four Methods of Correcting GPS Data: DGPS, WAAS, L-Band, and Postprocessing Dick Karsky, Project Leader
United States Department of Agriculture Engineering Forest Service Technology & Development Program July 2004 0471-2307–MTDC 2200/2300/2400/3400/5100/5300/5400/ 6700/7100 Comparing Four Methods of Correcting GPS Data: DGPS, WAAS, L-Band, and Postprocessing Dick Karsky, Project Leader he global positioning system (GPS) of satellites DGPS Beacon Corrections allows persons with standard GPS receivers to know where they are with an accuracy of 5 meters The U.S. Coast Guard has installed two control centers Tor so. When more precise locations are needed, and more than 60 beacon stations along the coastal errors (table 1) in GPS data must be corrected. A waterways and in the interior United States to transmit number of ways of correcting GPS data have been DGPS correction data that can improve GPS accuracy. developed. Some can correct the data in realtime The beacon stations use marine radio beacon fre- (differential GPS and the wide area augmentation quencies to transmit correction data to the remote GPS system). Others apply the corrections after the GPS receiver. The correction data typically provides 1- to data has been collected (postprocessing). 5-meter accuracy in real time. In theory, all methods of correction should yield similar In principle, this process is quite simple. A GPS receiver results. However, because of the location of different normally calculates its position by measuring the time it reference stations, and the equipment used at those takes for a signal from a satellite to reach its position. stations, the different methods do produce different Because the GPS receiver knows exactly where results. -
AFSPC-CO TERMINOLOGY Revised: 12 Jan 2019
AFSPC-CO TERMINOLOGY Revised: 12 Jan 2019 Term Description AEHF Advanced Extremely High Frequency AFB / AFS Air Force Base / Air Force Station AOC Air Operations Center AOI Area of Interest The point in the orbit of a heavenly body, specifically the moon, or of a man-made satellite Apogee at which it is farthest from the earth. Even CAP rockets experience apogee. Either of two points in an eccentric orbit, one (higher apsis) farthest from the center of Apsis attraction, the other (lower apsis) nearest to the center of attraction Argument of Perigee the angle in a satellites' orbit plane that is measured from the Ascending Node to the (ω) perigee along the satellite direction of travel CGO Company Grade Officer CLV Calculated Load Value, Crew Launch Vehicle COP Common Operating Picture DCO Defensive Cyber Operations DHS Department of Homeland Security DoD Department of Defense DOP Dilution of Precision Defense Satellite Communications Systems - wideband communications spacecraft for DSCS the USAF DSP Defense Satellite Program or Defense Support Program - "Eyes in the Sky" EHF Extremely High Frequency (30-300 GHz; 1mm-1cm) ELF Extremely Low Frequency (3-30 Hz; 100,000km-10,000km) EMS Electromagnetic Spectrum Equitorial Plane the plane passing through the equator EWR Early Warning Radar and Electromagnetic Wave Resistivity GBR Ground-Based Radar and Global Broadband Roaming GBS Global Broadcast Service GEO Geosynchronous Earth Orbit or Geostationary Orbit ( ~22,300 miles above Earth) GEODSS Ground-Based Electro-Optical Deep Space Surveillance -
GLONASS & GPS HW Designs
GLONASS & GPS HW designs Recommendations with u-blox 6 GPS receivers Application Note Abstract This document provides design recommendations for GLONASS & GPS HW designs with u-blox 6 module or chip designs. u-blox AG Zürcherstrasse 68 8800 Thalwil Switzerland www.u-blox.com Phone +41 44 722 7444 Fax +41 44 722 7447 [email protected] GLONASS & GPS HW designs - Application Note Document Information Title GLONASS & GPS HW designs Subtitle Recommendations with u-blox 6 GPS receivers Document type Application Note Document number GPS.G6-CS-10005 Document status Preliminary This document and the use of any information contained therein, is subject to the acceptance of the u-blox terms and conditions. They can be downloaded from www.u-blox.com. u-blox makes no warranties based on the accuracy or completeness of the contents of this document and reserves the right to make changes to specifications and product descriptions at any time without notice. u-blox reserves all rights to this document and the information contained herein. Reproduction, use or disclosure to third parties without express permission is strictly prohibited. Copyright © 2011, u-blox AG. ® u-blox is a registered trademark of u-blox Holding AG in the EU and other countries. GPS.G6-CS-10005 Page 2 of 16 GLONASS & GPS HW designs - Application Note Contents Contents .............................................................................................................................. 3 1 Introduction ................................................................................................................. -
AEN-88: the Global Positioning System
AEN-88 The Global Positioning System Tim Stombaugh, Doug McLaren, and Ben Koostra Introduction cies. The civilian access (C/A) code is transmitted on L1 and is The Global Positioning System (GPS) is quickly becoming freely available to any user. The precise (P) code is transmitted part of the fabric of everyday life. Beyond recreational activities on L1 and L2. This code is scrambled and can be used only by such as boating and backpacking, GPS receivers are becoming a the U.S. military and other authorized users. very important tool to such industries as agriculture, transporta- tion, and surveying. Very soon, every cell phone will incorporate Using Triangulation GPS technology to aid fi rst responders in answering emergency To calculate a position, a GPS receiver uses a principle called calls. triangulation. Triangulation is a method for determining a posi- GPS is a satellite-based radio navigation system. Users any- tion based on the distance from other points or objects that have where on the surface of the earth (or in space around the earth) known locations. In the case of GPS, the location of each satellite with a GPS receiver can determine their geographic position is accurately known. A GPS receiver measures its distance from in latitude (north-south), longitude (east-west), and elevation. each satellite in view above the horizon. Latitude and longitude are usually given in units of degrees To illustrate the concept of triangulation, consider one satel- (sometimes delineated to degrees, minutes, and seconds); eleva- lite that is at a precisely known location (Figure 1). If a GPS tion is usually given in distance units above a reference such as receiver can determine its distance from that satellite, it will have mean sea level or the geoid, which is a model of the shape of the narrowed its location to somewhere on a sphere that distance earth. -
A Highly Elliptical Orbit Space System for Hydrometeorological Monitoring of the Arctic Region by V
A highly elliptical orbit space system for hydrometeorological monitoring of the Arctic region by V. V. Asmus1, V. N. Dyadyuchenko2, Y. I. Nosenko3, G. M. Polishchuk4 and V. A. Selin3 The lack of reliable, frequently high latitudes. It has therefore been • Monitoring of climate change updated information on the Earth’s suggested that demonstration of polar ice caps is a signifi cant problem a hydrometeorological system of • Data collection and relay for weather forecasting, affecting satellites on highly elliptical orbit from land-, sea- and air-based forecast skill for the entire planet. The (HEO), called the “Arctica” system, observing platforms poor numerical weather prediction should be created to provide the (NWP) skill for the Arctic region necessary complex information for the • Exchange and dissemination of and the Earth’s northern territories diffi cult tasks involved in developing processed hydrometeorological is caused primarily by errors in the whole Arctic region. and heliogeophysical data. determining initial conditions, which depend on the quality of initial Signifi cantly, the hydrometeorological Further progress in global and data. Until now, initial data have observations carried out in the regional numerical weather prediction been received from meteorological Arctic within the framework of the depends to a large extent on: geostationary satellites, which are International Polar Year 2007-2008 not very effective in scanning high are not provided with remote-sensing • Quasi-continuous reception latitudes and polar-orbiting -
NASA Process for Limiting Orbital Debris
NASA-HANDBOOK NASA HANDBOOK 8719.14 National Aeronautics and Space Administration Approved: 2008-07-30 Washington, DC 20546 Expiration Date: 2013-07-30 HANDBOOK FOR LIMITING ORBITAL DEBRIS Measurement System Identification: Metric APPROVED FOR PUBLIC RELEASE – DISTRIBUTION IS UNLIMITED NASA-Handbook 8719.14 This page intentionally left blank. Page 2 of 174 NASA-Handbook 8719.14 DOCUMENT HISTORY LOG Status Document Approval Date Description Revision Baseline 2008-07-30 Initial Release Page 3 of 174 NASA-Handbook 8719.14 This page intentionally left blank. Page 4 of 174 NASA-Handbook 8719.14 This page intentionally left blank. Page 6 of 174 NASA-Handbook 8719.14 TABLE OF CONTENTS 1 SCOPE...........................................................................................................................13 1.1 Purpose................................................................................................................................ 13 1.2 Applicability ....................................................................................................................... 13 2 APPLICABLE AND REFERENCE DOCUMENTS................................................14 3 ACRONYMS AND DEFINITIONS ...........................................................................15 3.1 Acronyms............................................................................................................................ 15 3.2 Definitions ......................................................................................................................... -
Open Rosen Thesis.Pdf
THE PENNSYLVANIA STATE UNIVERSITY SCHREYER HONORS COLLEGE DEPARTMENT OF AEROSPACE ENGINEERING END OF LIFE DISPOSAL OF SATELLITES IN HIGHLY ELLIPTICAL ORBITS MITCHELL ROSEN SPRING 2019 A thesis submitted in partial fulfillment of the requirements for a baccalaureate degree in Aerospace Engineering with honors in Aerospace Engineering Reviewed and approved* by the following: Dr. David Spencer Professor of Aerospace Engineering Thesis Supervisor Dr. Mark Maughmer Professor of Aerospace Engineering Honors Adviser * Signatures are on file in the Schreyer Honors College. i ABSTRACT Highly elliptical orbits allow for coverage of large parts of the Earth through a single satellite, simplifying communications in the globe’s northern reaches. These orbits are able to avoid drastic changes to the argument of periapse by using a critical inclination (63.4°) that cancels out the first level of the geopotential forces. However, this allows the next level of geopotential forces to take over, quickly de-orbiting satellites. Thus, a balance between the rate of change of the argument of periapse and the lifetime of the orbit is necessitated. This thesis sets out to find that balance. It is determined that an orbit with an inclination of 62.5° strikes that balance best. While this orbit is optimal off of the critical inclination, it is still near enough that to allow for potential use of inclination changes as a deorbiting method. Satellites are deorbited when the propellant remaining is enough to perform such a maneuver, and nothing more; therefore, the less change in velocity necessary for to deorbit, the better. Following the determination of an ideal highly elliptical orbit, the different methods of inclination change is tested against the usual method for deorbiting a satellite, an apoapse burn to lower the periapse, to find the most propellant- efficient method. -
GEO, MEO, and LEO How Orbital Altitude Impacts Network Performance in Satellite Data Services
GEO, MEO, AND LEO How orbital altitude impacts network performance in satellite data services COMMUNICATION OVER SATELLITE “An entire multi-orbit is now well accepted as a key enabler across the telecommunications industry. Satellite networks can supplement existing infrastructure by providing global reach satellite ecosystem is where terrestrial networks are unavailable or not feasible. opening up above us, But not all satellite networks are created equal. Providers offer different solutions driving new opportunities depending on the orbits available to them, and so understanding how the distance for high-performance from Earth affects performance is crucial for decision making when selecting a satellite service. The following pages give an overview of the three main orbit gigabit connectivity and classes, along with some of the principal trade-offs between them. broadband services.” Stewart Sanders Executive Vice President of Key terms Technology at SES GEO – Geostationary Earth Orbit. NGSO – Non-Geostationary Orbit. NGSO is divided into MEO and LEO. MEO – Medium Earth Orbit. LEO – Low Earth Orbit. HTS – High Throughput Satellites designed for communication. Latency – the delay in data transmission from one communication endpoint to another. Latency-critical applications include video conferencing, mobile data backhaul, and cloud-based business collaboration tools. SD-WAN – Software-Defined Wide Area Networking. Based on policies controlled by the user, SD-WAN optimises network performance by steering application traffic over the most suitable access technology and with the appropriate Quality of Service (QoS). Figure 1: Schematic of orbital altitudes and coverage areas GEOSTATIONARY EARTH ORBIT Altitude 36,000km GEO satellites match the rotation of the Earth as they travel, and so remain above the same point on the ground. -
Orbital Debris Mitigation Standard Practices (ODMSP) Were Established in 2001 to Address the Increase in Orbital Debris in the Near-Earth Space Environment
U.S. Government Orbital Debris Mitigation Standard Practices, November 2019 Update PREAMBLE The United States Government (USG) Orbital Debris Mitigation Standard Practices (ODMSP) were established in 2001 to address the increase in orbital debris in the near-Earth space environment. The goal of the ODMSP was to limit the generation of new, long-lived debris by the control of debris released during normal operations, minimizing debris generated by accidental explosions, the selection of safe flight profile and operational configuration to minimize accidental collisions, and postmission disposal of space structures. While the original ODMSP adequately protected the space environment at the time, the USG recognizes that it is in the interest of all nations to minimize new debris and mitigate effects of existing debris. This fact, along with increasing numbers of space missions, highlights the need to update the ODMSP and to establish standards that can inform development of international practices. This 2019 update includes improvements to the original objectives as well as clarification and additional standard practices for certain classes of space operations. The improvements consist of a quantitative limit on debris released during normal operations, a probability limit on accidental explosions, probability limits on accidental collisions with large and small debris, and a reliability threshold for successful postmission disposal. The new standard practices established in the update include the preferred disposal options for immediate removal of structures from the near-Earth space environment, a low-risk geosynchronous Earth orbit (GEO) transfer disposal option, a long-term reentry option, and improved move-away-and-stay-away storage options in medium Earth orbit (MEO) and above GEO.